Macbook Pro won't recognise new internal HD, but sees old one fine...

I tried to replace my 160GB HD on my 2007 MBP with a Seagate Momentus 750GB drive today. Firstly I used SuperDuper to copy my OSX startup disk to the new drive, mounted in a USB caddy. I verified that the copy on the new drive was OK by alt-restarting my MBP with it connected in the caddy and selecting it as the startup disk. It started up fine.

So then I replaced my old HD with the new one, and started up. The drive was not recognised - I got the blinking questionmark folder... So I replaced the old HD and all was fine again. I did this twice, each time with the same result.

Does anyone know what might be causing this, and if I can solve the problem?

Thanks for the comments all. I eventually sorted it by installing the new drive in the MBP and repartitioning it using the Snow Leopard install disk, then installing a completely fresh OS and using Migration Assistant to take all my old stuff from the old HD in the USB caddy. Not sure why the SuperDuper created drive was not recognisable in the MBP in the first place.
Sean

Thanks for the comments all. I eventually sorted it by installing the new drive in the MBP and repartitioning it using the Snow Leopard install disk, then installing a completely fresh OS and using Migration Assistant to take all my old stuff from the old HD in the USB caddy. Not sure why the SuperDuper created drive was not recognisable in the MBP in the first place.
Sean

Hi all
Sorry i am reopening the case. Did you manage to fix it? It is surely so long ago, but could u still give me any hint?
I have exactly the same problem, but couldnt fix it. I installed a new HDD in my MPB (late 2009). It wasnt recognize; i then connect it through usb, format it, installed leopard on it. but as, i reinstalled it back into the mbp ==> same old problem... but the old hdd is recognized though.

Hi all
Sorry i am reopening the case. Did you manage to fix it? It is surely so long ago, but could u still give me any hint?
I have exactly the same problem, but couldnt fix it. I installed a new HDD in my MPB (late 2009). It wasnt recognize; i then connect it through usb, format it, installed leopard on it. but as, i reinstalled it back into the mbp ==> same old problem... but the old hdd is recognized though.

I'd appreciate any help, thanks!

Well, as I said, I put the new hard drive in to the MBP, used my Snow Leopard disk's disk utility to format it and then installed the OS on it, using migration assistant to bring back my data fro the old hd which I put into a USB caddy.
Good luck,
Sean

Well, as I said, I put the new hard drive in to the MBP, used my Snow Leopard disk's disk utility to format it and then installed the OS on it, using migration assistant to bring back my data fro the old hd which I put into a USB caddy.
Good luck,
Sean

Craaap... I did almost the same thing. I restored from my TM instead. I don't understand it :-(
Thanks for the reply!